The purpose of this study is to determine if either active memory or inhibition is a causal neurocognitive mechanism of formal thought disorder (FTD). Even though FTD has been considered an important symptom of schizophrenia since the formation of the schizophrenia concept (Andreasen, 1979; Bleuler, 1911/1950; Kraepelin, 1919/1971), it has been often noted that progress in understanding the causes of FTD has been slow (Maher, 1991; Rochester and Martin, 1979). We propose that much of the previous theory and research of FTD has been consistent in implicating two potential causal mechanisms of FTD: active memory and inhibition. However, previous research has confounded their measurement. This project will separately measure and manipulate active memory and inhibition. Two parts of the project will provide converging evidence about which of these two processes are causal mechanisms of FTD. In the first part, we will determine whether active memory or inhibition is associated with FTD in people with schizophrenia. In the second part of the project, active memory and inhibition will be directly manipulated in an analogue study to determine which process could be a causal mechanism of FTD.